1. Field of the Invention
This invention relates to a force sense imparting type input apparatus for imparting a force sense to an operation portion in accordance with an operating condition of the operation portion, and more particularly to over-heat prevention means of an actuator for imparting a force sense to the operation portion.
2. Description of Related Art
A force sense imparting type input apparatus including an operation portion operated by an operator, a position sensor for detecting an operating condition of the operation portion, an actuator for imparting a force sense to the operation portion, and a controller for controlling driving of the actuator in accordance with a position signal outputted from the position sensor and imparting a force sense corresponding to the operating condition of the operation portion to the operation portion has been proposed as an input apparatus to be applied to a bi-wire system car-mounted electric equipment concentrated control apparatus, a steering apparatus, a gear shift apparatus or a brake apparatus (refer to patent document 1, for example).
This force sense imparting type input apparatus can impart various kinds of force senses to the operation portion in accordance with an operating direction and an operating quantity of the operation portion. Therefore, a predetermined operation feeling can be imparted to the operation of the operation portion in various kinds of the bi-wire systems.
[Patent Document]
Japanese Patent Laid-Open No. 149324/2002 (FIG. 3)
In the force sense imparting type input apparatus applied to the steering apparatus, or the like, described above, driving power is always supplied to the actuator during driving of a vehicle and the actuator is likely to be over-heated. Therefore, various problems occur due to over-heating such as damage of the actuator, fuming, exothermy, and so forth.
From the aspect of prevention of over-heat of the actuator, it is preferred to cut off the supply of driving power to the actuator when the temperature of the actuator reaches a predetermined value. When this method is used, however, the force sense applied to the operation portion abruptly disappears during driving of the vehicle. Therefore, the operation of the steering apparatus, etc is likely to become unstable and an unnecessary strain is undesirably applied to the driver.
This problem also holds true of the case where the supply of driving power is again made to the actuator in a stage where the temperature of the actuator drops below a predetermined value after the supply of driving power to the actuator is once cut off. Because the force sense is abruptly imparted to the operation portion during driving of the vehicle, the operation of the steering apparatus, etc, is likely to become unstable and the unnecessary strain is forcibly applied to the driver.
To eliminate such problems of the related art technology, the invention aims at providing a force sense imparting type input apparatus that can prevent over-heat of an actuator without deteriorating operation stability of an operation portion.